What is a Jet Engines :-
A jet engine can also be called as a reaction engine because the reaction produced by the engine propels the aircraft or vehicle. Jet engines are internal combustion engines discharging hot exhaust gases at high velocity that generate thrust. Unlike the internal combustion engines in automobiles & trucks which convert the up & down movement of the piston to rotary movement of crankshaft, jet engines simply produces power by sucking air at the front side & discharging it at the back side.
What is Thrust?
Thrust is the forward force that pushes the engine and, therefore, the airplane forward. Sir Isaac Newton discovered that for "every action there is an equal and opposite reaction." An engine uses this principle. The engine takes in a large volume of air. The air is heated and compressed and slowed down. The air is forced through many spinning blades. By mixing this air with jet fuel, the temperature of the air can be as high as three thousand degrees. The power of the air is used to turn the turbine. Finally, when the air leaves, it pushes backward out of the engine. This causes the plane to move forward.
Parts in Jet Engines ?
Compressor
Combustor
Turbine
Nozzle
Working of jet engine ?
The compressor sucks the air & compresses it. This highly compressed air is then forced into combustion chamber.
Multiple nozzles inject fuel into the air & igniter(similar to spark plug) causes air to catch fire. The fuel burns with oxygen present in compressed air producing hot expanding gases.
These gases are passed through the turbines which causes the blades to rotate. This turning of turbine also rotates the shaft to which it is fixed. The same shaft in turn rotates the compressor. Which means instead of just letting out those hot gases, they are indirectly used to suck fresh air at the same time. This is the reason we need turbine after the combustion chamber section.
After coming out of the turbine, then the gases are allowed to exit the engine through a converging shaped nozzle.
The force of the exhaust gases pushing backwards(action) produces equal & opposite forward force(reaction)(Newton’s third law of motion). We call this forward force as thrust which powers the aircraft or vehicle forward.
Types of Jet Engines ?
Turbojet engines
Turbofan engines
Turboprop engines
Ramjets
Scram jets
Turbo-shafts
Interesting facts !
In 1903, the Wright Brothers flew, The Flyer, with a 12 horse power gas powered engine.
It was Frank Whittle, a British pilot, who designed and patented the first turbo jet engine in 1930. The Whittle engine first flew successfully in May, 1941.
Jet engines not only power aircraft but also cruise missiles & Unmanned Aerial Vehicles(UAV or we also call them drones).
A car named SSC Thrust, currently holding the land speed record, is powered by a jet engine.
